The asthma predictive index as a surrogate diagnostic tool in preschoolers: Analysis of a longitudinal birth cohort

Diagnosing asthma in preschool children remains an unsolved challenge, at a time when early identification would allow for better education and treatment to prevent morbidity and lung function deterioration.

OBJECTIVE

To evaluate if the asthma predictive index (API) can be used as surrogate for asthma diagnosis in preschoolers.

METHODS

Birth cohort of 339 pregnant women enrolled at delivery and their offspring, who were followed for atopy, wheezing, and other respiratory illnesses through 30 months of age. The API was determined at 30 months of age by the researchers; and examined its association with physician-diagnosed asthma during the first 30 months, made independently by the primary care physician not involved in the study.

RESULTS

Among 307 offspring with complete follow-up, 44 (14.3%) were API+. Maternal body mass index, maternal education, past oral contraceptive use, birthweight, placenta weight, age of daycare at 12 m, gastroesophageal reflux disease at 12 m, acute otitis media at 18 m, bronchiolitis, croup and pneumonia, cord blood adiponectin were all associated with API+. In the multivariable analysis, API+ was associated with almost sixfold odds of asthma diagnosis (adjusted OR = 5.7, 95% CI [2.6-12.3]), after adjusting for the relevant covariates above including respiratory infections like bronchiolitis and pneumonia. The API sensitivity was 48%, specificity 92%, 61% PPV, 88% NPV, 6.4 LR+, 0.56 LR-, 0.84 diagnosis accuracy. The adjusted odds for asthma was 11.4.

CONCLUSIONS

This longitudinal birth cohort suggests, for first time, that API (a structured definition for asthma), could be used as a diagnostic tool, not only as a prognostic tool, in toddlers and preschoolers.

Prevalence of recurrent wheezing in infants and toddlers in Barbados: findings from a prospective study of a cohort of babies born during 2015-2017

OBJECTIVES

The main objective was to determine the prevalence of recurrent wheezing (RW) among infants and toddlers as well as the prevalence of asthma predictive risk factors among those with RW.

MATERIALS AND METHODS

A prospective study of a cohort of babies recruited after their birth during July 2015-June 2017. Mothers were contacted using the WhatsApp messaging system for digital follow-up on their baby's condition at 3-monthly intervals until they were 18 months old. Information on wheezing and its correlates were collected by digital follow-up and corroborated at an in-person interview and examination of their baby at 18 months of age. Recurrent wheezing was defined as more than three episodes of wheezing or its correlates during the follow-up period.

RESULTS

There were 338 males (41.5%) and 476 (58.5%) females. Overall, 31.1% (95% CI = 27.9%, 34.4%) had RW by 18 months and the same number had RW during their first year of life. Of the infants with RW, 121 (47.8%; 95% CI = 41.6, 54.2) had at least one or both of the major criteria and/or at least two minor criteria of the stringent Asthma Predictive Index (API). Of those with RW, 32.0% received antihistamine and 20% had received antibiotics on their last visit to a physician for wheezing or symptoms of cough, cold, and/or breathing difficulty.

CONCLUSIONS

Nearly a third of infants and toddlers had RW and nearly half of the infants with RW had risk factors fulfilling the criteria of the stringent API.

Predicting Asthma Using Clinical Indexes

Asthma is no longer considered a single disease, but a common label for a set of heterogeneous conditions with shared clinical symptoms but associated with different cellular and molecular mechanisms. Several wheezing phenotypes coexist at preschool age but not all preschoolers with recurrent wheezing develop asthma at school-age; and since at the present no accurate single screening test using genetic or biochemical markers has been developed to determine which preschooler with recurrent wheezing will have asthma at school age, the asthma diagnosis still needs to be based on clinical predicted models or scores. The purpose of this review is to summarize the existing and most frequently used asthma predicting models, to discuss their advantages/disadvantages, and their accomplishment on all the necessary consecutive steps for any predictive model. Seven most popular asthma predictive models were reviewed (original API, Isle of Wight, PIAMA, modified API, ucAPI, APT Leicestersher, and ademAPI). Among these, the original API has a good positive LR~7.4 (increases the probability of a prediction of asthma by 2-7 times), and it is also simple: it only requires four clinical parameters and a peripheral blood sample for eosinophil count. It is thus an easy model to use in any rural or urban health care system. However, because its negative LR is not good, it cannot be used to rule out the development of asthma.

Usefulness of asthma predictive index in ascertaining asthma status of children using medical records: An explorative study

BACKGROUND

Frequent wheezing in original asthma predictive index (API) was defined by parental report of recurrent wheezing within 1 year during the first 3 years of life. The nature of frequent wheezing in children, particularly aged over 3 years, has not been studied. We aimed to assess the frequency and interval of wheezing to define frequent wheezing in ascertaining asthma for children using medical records.

METHODS

Among children who participated in a previous study (n = 427), all wheezing episodes documented in medical records were collected for children who had ≥2 wheezing episodes PLUS met one major criterion or two minor criteria of API. We compared the distribution of known risk factors for asthma between subjects having two consecutive wheezing episodes with shorter interval (≤1 year) compared to those with longer interval (1 to 3 years).

RESULTS

A total of 62 children met API at median age of 2.3 years. During follow-up period (median age: 11.3 years), a total of 198 wheezing episodes were observed. 81% of wheezing intervals were within 3 years from the earlier wheezing episode, including 60% within 1 year. Children who met API based on 1-year interval (n = 40) vs 1- to 3-year interval (n = 13) appeared to be similar in regard to the known risk factors for asthma.

CONCLUSIONS

Our exploratory study finding suggests that children who had frequent wheezing episodes with longer interval (<3 years) need to be considered to be determined as asthma cases when API is applied to retrospective medical records. Prospective studies with a larger sample size need to replicate this finding.

[Effect of obesity on treatment outcome of asthma predictive index-positive infants and young children with wheezing]

OBJECTIVE

To study the effect of obesity on the treatment outcome of asthma predictive index (API)-positive infants and young children with wheezing.

METHODS

A total of 208 API-positive infants and young children with wheezing were enrolled. According to the Kaup index, the patients were divided into an obese group (n=93) and a non-obese group (n=115). The patients were given multimodality therapy in an acute episode of wheezing and aerosol inhalation of inhaled corticosteroid (ICS) budesonide suspension in the remission stage. The dose of ICS was adjusted according to clinical control. The patients were treated for 6 months, and were followed up at 2 weeks after treatment and once per month afterwards.

RESULTS

At 2 weeks and 1 month after treatment, the obese group had significantly lower remission rates of clinical symptoms than the non-obese group (35.5%/75.3% vs 53.0%/87.8%; P<0.05). Compared with the non-obese group, the obese group had significantly higher incidence rates of wheezing at 3 and 6 months after treatment and a significantly higher proportion of patients who visited the emergency service or were hospitalized due to wheezing within 6 months (P<0.05).

CONCLUSIONS

Obesity can inhibit the response to ICS treatment in API-positive infants and young children with wheezing.

[Effect of obesity on treatment outcome of asthma predictive index-positive infants and young children with wheezing]

OBJECTIVE

To study the effect of obesity on the treatment outcome of asthma predictive index (API)-positive infants and young children with wheezing.

METHODS

A total of 208 API-positive infants and young children with wheezing were enrolled. According to the Kaup index, the patients were divided into an obese group (n=93) and a non-obese group (n=115). The patients were given multimodality therapy in an acute episode of wheezing and aerosol inhalation of inhaled corticosteroid (ICS) budesonide suspension in the remission stage. The dose of ICS was adjusted according to clinical control. The patients were treated for 6 months, and were followed up at 2 weeks after treatment and once per month afterwards.

RESULTS

At 2 weeks and 1 month after treatment, the obese group had significantly lower remission rates of clinical symptoms than the non-obese group (35.5%/75.3% vs 53.0%/87.8%; P<0.05). Compared with the non-obese group, the obese group had significantly higher incidence rates of wheezing at 3 and 6 months after treatment and a significantly higher proportion of patients who visited the emergency service or were hospitalized due to wheezing within 6 months (P<0.05).

CONCLUSIONS

Obesity can inhibit the response to ICS treatment in API-positive infants and young children with wheezing.

Effect of indoor air quality of day care centers in children with different predisposition for asthma

BACKGROUND

Scarce information is available about the relationships between indoor air quality (IAQ) at day care centers (DCC), the estimated predisposition for asthma, and the actual wheezing susceptibility.

METHODS

In the Phase II of ENVIRH study, 19 DCC were recruited after cluster analysis. Children were evaluated firstly using the ISAAC questionnaire and later by a follow-up questionnaire about recent wheezing. A positive asthma predictive index (API) was considered as predisposition for asthma. Every DCC was audited for IAQ and monitored for chemical and biologic contaminants.

RESULTS

We included 1191 children, with a median age of 43 (P25 -P75 : 25-58) months. Considering the overall sample, in the first questionnaire, associations were found between CO2 concentration (increments of 200 ppm) and diagnosis of asthma (OR: 1.10; 95% CI: 1.00-1.20). Each increment of 100 μg/m(3) of total volatile organic compounds (TVOC) and 1 μg of Der p1/g of dust were associated with wheezing in the previous 12 months (OR: 1.06; 95% CI: 1.01-1.11 and OR: 1.06; 95% CI: 0.99-1.12, respectively). In the follow-up questionnaire, TVOC were again associated with wheezing (OR: 1.05; 95% CI: 1.00-1.11). Children exposed to fungal concentration above the 75th percentile had also higher odds of wheezing at follow-up. TVOC were associated with wheezing in children with either negative or positive API.

CONCLUSIONS

IAQ in DCC seems to be associated with wheezing, in children with and without predisposition for asthma.

Asthma-predictive-index, bronchial-challenge, sputum eosinophils in acutely wheezing preschoolers

BACKGROUND

Most preschoolers with viral wheezing exacerbations are not atopic.

AIM

To test in a prospective controlled trial whether wheezing preschoolers presenting to the ED are different from the above in three different domains defining asthma: the atopic characteristics based on stringent asthma predictive index (S-API), the characteristics of bronchial hyper-responsiveness (BHR), and airway inflammation.

METHODS

The S-API was prospectively collected in 41 preschoolers (age 31.9 ± 17.4 months, range; 1-6 years) presenting to the ED with acute wheezing and compared to healthy preschoolers (n = 109) from our community (community control group). Thirty out of the 41 recruited preschoolers performed two sets of bronchial challenge tests (BCT)-(methacholine and adenosine) within 3 weeks and following 3 months of the acute event and compared to 30 consecutive ambulatory preschoolers, who performed BCT for diagnostic workup in our laboratory (ambulatory control group). On presentation, induced sputum (IS) was obtained from 22 of the 41 children.

OUTCOMES

Primary: S-API, secondary: BCTs characteristics and percent eosinophils in IS.

RESULTS

Significantly more wheezing preschoolers were S-API positive compared with the community control group: 20/41 (48.7%) versus 15/109 (13.7%, P < 0.001). All methacholine-BCTs-30/30 (100%) were positive compared with 13/14 (92.8%) in the ambulatory control group (P = 0.32). However, 23/27 (85.2%) were adenosine-BCT positive versus 3/17 (17.5%) in the ambulatory control group (P < 0.001). Diagnostic IS success rate was 18/22 (81.8%). Unexpectedly, 9/18 (50.0%) showed eosinophilia in the IS.

CONCLUSIONS

Wheezing preschoolers presenting to the ED is a unique population with significantly higher rate of positive S-API and adenosine-BCT compared with controls and frequently (50%) express eosinophilic airway inflammation.

Development and initial testing of Asthma Predictive Index for a retrospective study: an exploratory study

OBJECTIVE

Asthma Predictive Index (API) has been used for predicting asthma in prospective or cross-sectional studies, not for a retrospective study. We aim to develop and validate API for a retrospective study.

METHODS

This is a cross-sectional study based on a convenience sample of children who participated in a previous retrospective cohort study. API was operationalized by two or more wheezing episodes in a year during the first 3 years of life PLUS one of the major or two of the minor criteria of the original API. We assessed validity of retrospective API against Predetermined Asthma Criteria (PAC) which has been extensively used in clinical studies for asthma. We assessed criterion validity by measuring kappa and agreement rate between API and PAC and construct validity by determining associations of API with known risk factors for asthma.

RESULTS

Of the eligible 105 children, 55 (52.4%) were male, 90 (85.7%) Caucasians, and the mean age (±SD) was 5.8 years (±1.5). API criteria was met by 15 (14.3%), compared to 33 (31.4%) by PAC, respectively. The agreement rate and kappa between API and definite asthma of PAC were 89.5% and 0.66 (p < 0.01). Atopic conditions, lower parental education, no history of breastfeeding and family history of asthma were significantly associated with risk of asthma by API.

CONCLUSIONS

Application of API to a retrospective study for ascertaining asthma status is suitable. Our study findings need to be replicated by future studies with a larger sample size.

Daily vs. intermittent inhaled corticosteroids for recurrent wheezing and mild persistent asthma: a systematic review with meta-analysis

BACKGROUND

Intermittent ICS treatment with SABA in response to symptoms, is an emerging strategy for control of mild-to-moderate asthma, and recurrent wheezing. This systematic revue compares the efficacy of daily vs. intermittent ICS among preschoolers, children and adults with persistent wheezing and mild to moderate stable persistent asthma.

METHODS

Systematic review of randomized, placebo-controlled trials with a minimum of 8 weeks of daily (daily ICS with rescue SABA during exacerbations) vs. intermittent ICS (ICS plus SABA at the onset of symptoms), were retrieved through different databases. Primary outcome was asthma exacerbations; secondary outcomes were pulmonary function tests, symptoms, days without symptoms, SABA use, corticosteroids use, days without rescue medication use, expired nitric oxide and serious adverse events.

RESULTS

Seven trials (1367 participants) met inclusion criteria there was no statistically significant difference in the rate of asthma exacerbations between those with daily vs. intermittent ICS (0.96; 95% CI: 0.86, 1.06, I(2) = 0%). In the sub-group analysis, no differences were seen in duration of studies, step-up strategy or age. However, compared to intermittent ICS, the daily ICS group had a significant increase in asthma-free days and non-significant decreases in rescue SABA use and exhaled nitric oxide measurement.

CONCLUSIONS

No significant differences between daily and intermittent ICS in reducing the incidence of asthma exacerbations was found. However, the daily ICS strategy was superior in many secondary outcomes. Therefore, this study suggests to not change daily for intermittent ICS use among preschoolers, children with persistent wheezing and adults with mild-to-moderate stable persistent asthma. International prospective register of systematic reviews http://www.crd.york.ac.uk/PROSPERO/ (CRD42012003228).